Seminar Dosen Tamu, 28 Juni 2013 (09.00 – 11.00) Prof. C. Bubeck, MPIP Mainz, Jerman


Polymers for Optoelectronics:
Perspectives and Recent Studies

Christoph Bubeck
Max Planck Institute for Polymer Research, Mainz, Germany

Functional polymers are raising much current interest because of their promising application perspectives in plastic electronics and optoelectronics. To enable specific functions in organic light emitting diodes, solar cells, field-effect transistors, modulators in integrated optical circuits or others, the polymers must have semiconducting properties which arise from their conjugated, highly delocalized π-electron system.

The demanded materials properties for various applications require either large electrical conductivity or large optical transparency. It turns out that both requests are hard to satisfy simultaneously. Therefore, different strategies have evolved to optimize the materials for each specific application type by controlling the intrinsic aggregation tendencies of conjugated polymers, which are based on the rigidity of their polymer backbones.

Our work focuses on the question how the morphology of thin films of two model polymers (alkyl-substituted poly-para-phenylenevinylenes and poly-3-alkyl-thiophenes) depends on molecular weight, type of substitution and film preparation conditions. The morphology characterization is performed by polarized UV-Vis- / IR-reflection – transmission spectroscopy and optical waveguide studies, which provides information on the average polymer chain orientation with respect to the layer plane and the relative amount of aggregated chains with crystalline or liquid-crystalline order as compared to amorphous regions. Our aim is an improved understanding how the polymer structure and the thin film preparation parameters influence the morphology of thin films.